Timing confusion

calling911 · 12-31-2008, 06:25 AM

76 2.7l. modification if any unknown:

Timing light: craftsman with dial.

Observations:

Upon initial timing I noticed that the mark to the right of the two close together marks (which I think are 5d btdc and tdc) is my 0 mark.. I only say that cuz well, at idle its closest to the tic on the fan housing.

So could this be a gear situation on the distributor? Im confused.. when I set my timing light to 0 degrees and rev to 4-5-6k I dont see ANY timing mark even close..

Assuming my 2.7 is stock should I go ahead and set it to 35 BTDC at 5k or so? That should be max right? Not sure I want to take the time right now to "fix" this gear position issue.. could it be 180 off?

Im sure Im missing something.. I spent 2 hrs last not searching.. and all I know is this:

My fan housing says 5 degrees ATDC (I assume thats with vacum?)

If I set it to 5 degrees BTDC without vacumn my max advance is only 25 (this is where I have it set to now).

I THINK a stock compression 2.7 is supposed to be 35 btdc max based on what I read..

I will say this.. when I started this I was at 5d ATDC with no vacum. and I didnt know why my car wouldnt start right. Now it starts on the first turn.. which is nice.

Lots of questions.. I guess if I had to have one answered it would be:

What should I set the max to? And once Ive done that where should it be at idle with and without the vacumn connected.. to be clear, mine is the vacumn retard type.

I just realized something: the mark I am using since its not one of the two that are close together might be completely useless.. damn Im gonna need to fix this arent I?

Bill Verburg · Bill Verburg's Garage

the vacuum at idle when it is connected will retard timing by ~5*, check the timing w/ and w/o the vacuum hooked up. You should be able to see the difference. w/o vac it will be ~0*, w/ vac ~5*ATDC

Full advance w/o any vacuum is somewhere ~ 35*BTDC, but is not usually speced for that model

calling911 · 12-31-2008, 07:10 AM

Quote:

Originally Posted by Bill Verburg

the vacuum at idle when it is connected will retard timing by ~5*, check the timing w/ and w/o the vacuum hooked up. You should be able to see the difference. w/o vac it will be ~0*, w/ vac ~5*ATDC

Full advance w/o any vacuum is somewhere ~ 35*BTDC, but is not usually speced for that model

Yes I have the Porsche manual and all it says is 5 atdc. And yes, the vacumn is working as described.

GUess I'll just set it to 35 with no vacumn and leave it disconnected.. I cant get it to run worth a damn with it connected. But this doesnt answer my pulley question.. I'll just assume the single mark that has nothing next to it is my TDC.. but that doesnt make sense.. how would Porsche have you set it with a single mark? Youd have nothing to set the 5 degrees if you didnt have an adjustable light.. very confusing.

ossiblue · 12-31-2008, 07:31 AM

The two pulley marks are for TDC and 5*after TDC. The mark on the right is your TDC mark, as you discovered. Look closely at the face of the pulley when the TDC mark is lined up and see if you can find the Z1 mark just below it (on the face of the pulley).

With the engine warm and at idle, the 5* mark should be aligned with the vacuum line attatched as it is a retard vacuum. Try starting the car as you have, let it warm, then set the idle timing with vacuum attached. You may have to adjust the idle screw a bit. If you can't get a smooth idle and start with the vacuum attached, you may have another issue causing the hard/no start.

BTW, the single mark on the pulley may be one of the 120* marks used for valve adjustments. You are correct about Porsche having two marks together for idle timing. If you were 180* off, no way your car would start.

calling911 · 12-31-2008, 07:34 AM

Quote:

Originally Posted by ossiblue

The two pulley marks are for TDC and 5*after TDC. The mark on the right is your TDC mark, as you discovered. Look closely at the face of the pulley when the TDC mark is lined up and see if you can find the Z1 mark just below it (on the face of the pulley).

With the engine warm and at idle, the 5* mark should be aligned with the vacuum line attatched as it is a retard vacuum. Try starting the car as you have, let it warm, then set the idle timing with vacuum attached. You may have to adjust the idle screw a bit. If you can't get a smooth idle and start with the vacuum attached, you may have another issue causing the hard/no start.

BTW, the single mark on the pulley may be one of the 120* marks used for valve adjustments. You are correct about Porsche having two marks together for idle timing. If you were 180* off, no way your car would start.

There are no Z marks on my pulley.. I searched long and HARD..

I can;t get to the two marks together at all.. I run out of adjustment. I can only adjust to the single mark.. something is messed up.

pozee · 12-31-2008, 08:18 AM

If you're looking at the pulley from above and the two marks are at 12 o'clock (as an example), then the Z mark should be about an inch or so to the left of the two marks.

Not doubting you...but if it's the stock setup, there should be a Z mark.

calling911 · 12-31-2008, 08:21 AM

Quote:

Originally Posted by pozee

If you're looking at the pulley from above and the two marks are at 12 o'clock (as an example), then the Z mark should be about an inch or so to the left of the two marks.

Not doubting you...but if it's the stock setup, there should be a Z mark.

No, you should doubt me, you dont know me.. no offense.. but I will keep looking..

.. I'll try and take some photos for you.. I'll show you which mark is the ONLY mark i can get the distributor to move to at idle.. then you will know if Im screwed up I guess..

Back out to the shop...

ossiblue · 12-31-2008, 08:33 AM

Quote:

Originally Posted by calling911

There are no Z marks on my pulley.. I searched long and HARD..

I can;t get to the two marks together at all.. I run out of adjustment. I can only adjust to the single mark.. something is messed up.

O.K. I'm a bit confused, but that's not unusual. Are the two marks you just mentioned the 35*+/- BTC marks or the TDC, 5*ATDC marks? Maybe we're talking about two different things--I was referring to timing at idle and you often mentioned timing at 5K--full curve.

Going back to your original post, when you remove the distributor cap and the rotor is pointing to the #1 cylinder notch on the distributor body, do the two marks (TDC, 5* ATDC) line up? If so then you're not one tooth off. If this is how the static situation looks, everything sounds good so far. If not, maybe try this:

Take out the #1 spark plug. Insert a long straw or dowel into the plug hole. Rotate the engine until the dowel/straw is pushed out as far as it will go--you are at TDC. See if the rotor is pointing to the notch on the distributor body.

Where is the single mark you mention, relative to the TDC mark? Your full curve timing marks should be to the right of the TDC mark. Is this the mark that shows when you time at high rpm? With the TDC mark line up, try putting a little spot of "white out" on the marks to the right. Are these the marks that appear?

calling911 · 12-31-2008, 08:54 AM

Quote:

Originally Posted by ossiblue

O.K. I'm a bit confused, but that's not unusual. Are the two marks you just mentioned the 35*+/- BTC marks or the TDC, 5*ATDC marks? Maybe we're talking about two different things--I was referring to timing at idle and you often mentioned timing at 5K--full curve.

Going back to your original post, when you remove the distributor cap and the rotor is pointing to the #1 cylinder notch on the distributor body, do the two marks (TDC, 5* ATDC) line up? If so then you're not one tooth off. If this is how the static situation looks, everything sounds good so far. If not, maybe try this:

Take out the #1 spark plug. Insert a long straw or dowel into the plug hole. Rotate the engine until the dowel/straw is pushed out as far as it will go--you are at TDC. See if the rotor is pointing to the notch on the distributor body.

Where is the single mark you mention, relative to the TDC mark? Your full curve timing marks should be to the right of the TDC mark. Is this the mark that shows when you time at high rpm? With the TDC mark line up, try putting a little spot of "white out" on the marks to the right. Are these the marks that appear?

Im very sorry.. I just wasted your time.. I didnt have the light on the #1 wire. Now that its on #1 I see the two marks and I set it to the 5 ATDC mark with the vacumn connected. But I only get 30 full advance with this..

So, also.. I managed to break my tach. How you ask? Well I dont know.. Ihave a cheapy tach/dwell meter.. you hook one end to ground and one to the negative of the coil.. well I have a MSD coil and didnt know which was which.. I hooked it up and it didnt work then I moved it and it did. I went about my business and set the timing and now my tach in the car is off 200 RPM.. how do I know? I have a laser tech meter that read rpm off of any moving object that I verified it with.. its the same as my cheapie tach.. which means my Porsch tach is HOSED.

I never had to install that MSD tach thingamabob.. maybe I do now it something... anyway.. off subject I know.. Im just a pit miffed right now..

Anyway.. So I bet my dist. is about right.. Im guessing factory it should be right around 30.. shoot I didnt check without the vacumn DISconnected.. I'll have a look at that..

I've never tried to make the car work with the vacumn line connected but my timing has been way off everytime I tried it...

Now its right so Im out for a test drive..

Again, sorry about the screw up.. I traced what I thought was the #1 wire twice and got it wrong both times!

ossiblue · 12-31-2008, 09:16 AM

Don't apologize, we've all been there...
I just took a break to walk my dogs and was thinking of your dilemma and had the idea that maybe you had your light connected to the wrong wire--something I've done--and was going to suggest that. Glad you found it, and glad your problem with timing is solved. Now, on to the tach...

Gogar · 09:26 AM

I dont' know if these apply to Mid-Year 2.7 cars, but if your pulley moves CLOCKWISE, it pretty much does.

The spec in Haynes for a 2.7 (like Bill said) 5ATDC with the vaccum hooked up, and 32-38 BTDC full advance with the line unhooked.

+1 make sure your timing light is on #1 plug wire! If your timing light is on the wrong wire, it's possible you could be looking at those 120 degree and 240 degree marks and getting confused.

calling911 · 12-31-2008, 09:47 AM

Quote:

Originally Posted by Gogar

I dont' know if these apply to Mid-Year 2.7 cars, but if your pulley moves CLOCKWISE, it pretty much does.

The spec in Haynes for a 2.7 (like Bill said) 5ATDC with the vaccum hooked up, and 32-38 BTDC full advance with the line unhooked.

+1 make sure your timing light is on #1 plug wire! If your timing light is on the wrong wire, it's possible you could be looking at those 120 degree and 240 degree marks and getting confused.

Thanks.. yeah Im not getting full advance.. now I am only seeing 25 with or without the vacumn connected.. so I guess its time to tear down the distributor.

I dont know what could have happened to my tach. It kinda pulsates at idle which leads me to believe Im getting some sort of cross talk.. Im thinking bad ignition wire or something. I tried moving the wires away from the pickup wires with no success.. I assume the tach gets its signal off the same wire the cis uses off the distributor.

Anyway.. I guess I have some HP left on the table.. a good 10 degrees worth! Not sure what its worth but I MUST have it.

Sorta glad all this happened or I might not have known about the lost advance. I suppose I could just set it for more advance down low.. I guess some of the porsche "hot rods" use this method? I mean like the carerra's and such.. I dont know just spewing what I read last night.. I suppose I ought to check the # on the dist.. maybe its been replaced.. might have a different curve. Or, maybe 25 is correct for my car.. it IS a california car after all.. all bets are off.

Oh I took it out for a quick drive and with the timeing set right I can now run with my vacumn line connected.. which is cool cuz I always hated it dangling in there.. Seems to drive just fine.. no stumble or anything..

calling911 · 12-31-2008, 11:19 AM

Solved the tach problem.. something changed.. not sure what or how but I had to connect my tach up to the MSD tach port.. now it seems to be fine.

Talk about a waste of a day.. holy cow.. still not there yet.. the way I mounted my MSD I have no access to put a plug in the tach port.. so the fun continues.. Thats ok I didnt have anything else better to do.. NOT.